linux-kernel - Re: [RFC PATCH 1/5] dt-bindings: mfd: x-powers,axp152: Add polyphased property

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Message-ID: <20250922181611.GA567602-robh@kernel.org>
Date: Mon, 22 Sep 2025 13:16:11 -0500
From: Rob Herring <robh@...nel.org>
To: Andre Przywara <andre.przywara@....com>
Cc: Lee Jones <lee@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>, devicetree@...r.kernel.org,
	linux-sunxi@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Mikhail Kalashnikov <iuncuim@...il.com>
Subject: Re: [RFC PATCH 1/5] dt-bindings: mfd: x-powers,axp152: Add
 polyphased property

On Fri, Sep 19, 2025 at 01:00:16AM +0100, Andre Przywara wrote:
> Some X-Powers AXP PMICs can combine some of their DC/DC buck converter
> outputs in a multi-phase fashion, to achieve higher currents and
> decrease the output ripple. The datasheets call this poly-phase. This is
> programmable in the PMIC, although often set up as the PMIC's reset
> default.
> 
> Add the "x-powers,polyphased" property to the binding, to describe those
> pairs or tuples of regulators that should work together. In the lead
> regulator node, the property lists the phandles of the connected
> regulators. Just an empty property means no poly-phasing.

Don't we have a coupled regulator binding already?

> Signed-off-by: Andre Przywara <andre.przywara@....com>
> ---
>  .../devicetree/bindings/mfd/x-powers,axp152.yaml   | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml b/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
> index 45f015d63df16..260c4c0afc475 100644
> --- a/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
> +++ b/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
> @@ -304,6 +304,15 @@ properties:
>                noise. This probably makes sense for HiFi audio related
>                applications that aren't battery constrained.
>  
> +          x-powers,polyphased:
> +            $ref: /schemas/types.yaml#/definitions/phandle-array
> +            description:
> +              A list of phandles pointing to other regulators that should be
> +              polyphased with this regulator. The linked regulators will be
> +              synchronised with this regulator, within the PMIC, but only if
> +              supported by the PMIC. An empty list means this regulator
> +              should be configured in a single-phase setup.

phandle-array is poorly named and is really a matrix because you can 
have arg cells. So you need:

items:
  maxItems: 1

And is there an outer max for linked regulators?

Rob